A navi-server is proposed, which is configured to create road traffic information on the basis of probe information that is collected from a navi-client having a position measurement function, the probe information representing time-series measurement positions of the navi-client (see Patent Literature 1). Herein, “navi” is a short form of the word “navigation”. A technique of acquiring image data from a mobile terminal device equipped with a navigation function and displaying the image data on a vehicle-mounted touch-panel type display is proposed (see Patent Literature 2).